I. Field of the Invention
This invention relates generally to vehicle seats, and more particularly to vehicle seats which are effectively isolated from the effects of road shock and forces due to sudden acceleration and deceleration of the vehicle.
II. Discussion of the Prior Art
It is well known that semi-tractor trucks and other truck-type commercial vehicles tend to have a relatively stiff suspension system, whereby shock and vibration forces occasioned from traversing road bumps and the like are effectively transmitted to the driver and/or passenger in the vehicle. Likewise, when traveling at normal highway speeds and especially during acceleration and deceleration, there is a tendency for the driver or passenger to be lurched forward or rearward, depending upon the magnitude of the deceleration and acceleration vectors.
To improve the comfort of the ride, it is desirable, as much as possible, to isolate the seat occupant from these types of inertial forces. There are disclosed in the prior art various systems for isolating a vehicle driver or passenger from bouncing or jolting in the vertical direction, but compensation for fore and aft translation due to acceleration and deceleration have not been addressed. For example, in the Thompson et al. U.S. Pat. No. 3,990,668, a vehicle seat is described which incorporates a hydraulic actuator coupled in circuit with a valve whose spool is directly connected by linkages to the seat. The valve is operative to change the response of an accumulator coupled to the actuator so as to cushion the ride and to accommodate large excursions from a predetermined ride position due to major shocks. The Thompson et al. reference has no provision for cushioning or dampening fore and aft movement of the seat system. Other patents incorporating pneumatic cylinders or air bags operate strictly to adjust the height of the seat above the floor so as to accommodate drivers/passengers of differing physical stature. In this regard, reference is made to the Costin U.S. Pat. No. 3,954,245 and the Misher et al. U.S. Pat. No. 4,638,982. Neither of these patents teaches a seat construction for minimizing or nulling out fore and aft sway of the seat under breaking and acceleration conditions, respectively.